The present invention relates to gas burning lanterns. In particular, the present invention relates to a gas burning lantern with an improved regulator and an improved choke.
A conventional gas burning lantern may include a refillable fuel storage tank, a fuel delivery apparatus, and a burner attached to the fuel delivery apparatus. The fuel delivery apparatus may include a regulator and other equipment, such as an operator gas flow controller or tubing. The burner may include a mantle which, when ignited with a fuel/air mixture provided by the fuel delivery apparatus, emits a bright light. The mantle in such a lantern contains a catalyst, such as yttrium-oxide, which converts the heat from the flame into light. The burner may be covered by a transparent glass globe. Fuel used with such lanterns may include LPG, liquid propane or butane.
The regulator in such a lantern accepts gas from a gas source and provides a steady, controlled gas stream as an output. The regulator or another mechanism mixes air with the gas flow to produce an air/fuel mixture. In order to control and regulate gas flow, a valve allowing gas to flow through the regulator may be closed or narrowed as gas pushes against a diaphragm assembly in the regulator. The narrowing of the valve lowers the gas flow through the regulator, lowering the pressure on the diaphragm and thus allowing the valve to open somewhat. As gas initially flows, an equilibrium is quickly established where the diaphragm accepts a certain amount of gas pressure and in turn allows the valve to open a certain amount. Thus a regulated gas flow of relatively constant pressure may be produced. A regulator may have a control mechanism allowing a user to stop the flow of gas through the regulator in order to turn the lantern on or off. Such mechanisms engage the diaphragm assembly or another portion of the regulator to open or close the valve in the regulator.
A conventional regulator may allow gas to enter through a passage and then to leave the regulator through a passage which is more or less at a 90 degree angle from the entry passage. Thus, in such a regulator, gas may not exit the regulator travelling in the same direction as which it entered (for example, entering the regulator through the bottom and leaving through the top), as the diaphragm assembly provides a barrier around which gas cannot flow. This may dictate an awkward component arrangements. To allow for a better arrangement of components, it is desirable to have gas exit the regulator in the same direction which it entered. Alternately, the gas may exit in the same direction as which it entered, but may travel in a circuitous path or have its path shifted, due to the barrier of the diaphragm. This, too, may result in an undesirable arrangement of components.
Some regulator designs allow gas to flow straight through the regulator, in the same direction which the gas enters, by including a tube or opening through the diaphragm assembly. Gas then may flow up through the regulator. However, such regulators either lack control mechanisms allowing the user to regulate the flow of gas or include awkward control mechanisms. For example, an arm may connect to the diaphragm assembly to allow a user to turn the flow of gas on or off. The arm extends out of the regulator and out of the lantern, and swings in a semi-circle as it is turned around the side of the lantern. Such a design has a large profile and is awkward, as the swing of the arm takes up a large amount space. Other designs have control mechanisms separate from a diaphragm assembly or separate from a regulator. Such extra equipment adds to the complexity and expense of the lantern.
The mantle in a conventional lantern is most efficient at producing light when operating at relatively high temperatures. The lantern flame burns hotter with leaner air/fuel mixtures; i.e., with higher air/fuel ratios. However, leaner gas mixtures are harder to light, particularly when a lantern is cold, and particularly if a mechanical lighting mechanism (e.g., an igniter and spark wire) is used rather than an open flame from a match. A richer air/fuel mixture allows for easier lighting, but is less efficient.
The air/fuel mixture may actually get richer after the lantern heats up. The amount of gas flowing from the lantern""s gas tank to the mantle may remain constant over various operating conditions. However, the amount of air entering the system to mix with the gas is affected by the pressure in the system. A flame operating in a hot lantern may cause back pressure through the system, lowering the amount of air entering the lantern and creating a richer mixture.
Current designs attempt to solve the problem of providing a lantern which is both efficient and easy to light in various manners. Certain lanterns set the air/fuel mixture at an intermediate level which allows relatively easy lighting but which also allows for reasonable efficiency. Such a solution is imperfect, as the lantern is neither optimally efficient nor optimally easy to light. Other lanterns include a user operated choke which allows a user to alter the air/fuel mixture so that it is rich on lighting and lean during operation. Such chokes may require a separate control from the control used to operate the gas flow and the control used to operate the lighter which lights the lantern, requiring more equipment and expense, more complicated equipment, and requiring more and more complex user action during lighting. Such chokes may require two hands to operate.
It is desirable to have a regulator which allows gas to exit the regulator in the same direction which it enters (e.g., through the top of the regulator) and in addition which has a simple, easy to use, low profile, low cost, integral mechanism for allowing a user to control the flow of gas through the regulator. It is desirable to have a choke and ignition mechanism in a gas lantern which is simple and easy to operate, and which allows for one handed operation.
A gas operated lantern includes a control mechanism whereby a user may start gas flow through the lantern, operate a choke, and ignite the lantern. The user may perform these operations using the same control in an easy, simple series of motions. Preferably, the user rotates a knob, rotating a stem, to start gas flow and presses the knob axially inward along the stem to operate a choke and an igniter.